Higher gas prices, …

Though I’ve heard arguments against tip #8 – keeping your car clean. The contrarian view is that sharks have rough skin and are very efficient swimmers. So much so that the body suits the Olympians wear have little “teeth” sticking up to act as small air foils, improving hydrodynamic drag. And if that works there, what about the particles of dust on the car reducing aerodynamic drag? But maybe there’s a study on it somewhere.